JP3513387B2 - Pipe inner surface welding equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe inner surface welding device, and more particularly to a pipe inner surface welding device for a small diameter pipe hole in a pressure pipe or a fuel control housing of a nuclear power plant.

[0002]

2. Description of the Related Art FIG. 7 shows a pressure pipe b fixed to an upper lid a of a pressure vessel in a nuclear power plant and having a small diameter pipe hole inside. This pressure pipe b is formed by butt welding a U-shaped open welded joint. The inside of the welded welded joint expands like a bag into the small diameter pipe hole. When welding a long pressure pipe having such a structure from the outside in a welded joint, complete penetration welding up to the rear surface c of the welded joint is required. Therefore. After welding, it is necessary to confirm the state of the backside wave on the back surface c of the welded joint by visual inspection or nondestructive inspection. If there is an incomplete backside welded portion, repair welding must be performed from the inside of the welded joint.

[0003]

However, although a device for welding from the inner surface of the pipe has been conventionally used for a large diameter pipe, there is no device applicable to a small diameter pipe having the above-mentioned pipe structure. There is a problem that proper repair welding cannot be performed.

Therefore, the present invention has been made to solve such a problem, and in order to secure the soundness of the welded joint, the inner surface of the welded joint which passes through the pipe hole of the pipe and is expanded in a bag shape. It is an object of the present invention to provide a pipe inner surface welding device capable of repair-welding a backside welded part of the pipe.

[0005]

In order to achieve the above object, a pipe inner surface welding apparatus according to the present invention according to claim 1 is
A welding torch that is movable in the radial direction with respect to the pipe to be welded, an arc monitoring device having a field of view in the moving direction of the welding torch, the arc monitoring device and the welding torch, and the welding torch. A welding head provided with a driving device for moving in a radial direction; a rod member provided with a rotation driving device for holding the welding head and rotating the welding head in a circumferential direction with respect to the pipe to be welded; A rod member attached to the pipe to be welded, and a fixture having an adjuster capable of adjusting the amount of axial movement of the pipe to be welded.

In the pipe inner surface welding device according to the present invention as defined in claim 2, the arc monitoring device is a fiber type CC.
The welding head is a D camera, and the welding head is provided with a light shielding filter capable of opening and closing the field of view of the CCD camera.

[0007]

DETAILED DESCRIPTION OF THE INVENTION An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing an outline of a pipe inner surface welding apparatus according to an embodiment of the present invention.
Is an enlarged view of the main part. A long pressure pipe b is attached to an upper lid a of a pressure vessel in a nuclear power plant or the like, and there is a butt welded portion of a welded joint in the middle of the pressure pipe b. A bag-shaped space exists inside the butt-welded welded joint. The pipe inner surface welding apparatus according to the present invention is capable of repairing the welded portion on the back surface c of the welded joint in this bag-shaped space, guiding the welding torch 2 for repairing the welded portion, and positioning welding direction. The guide pipe 3 and the flexible pipe 4 containing various cables are connected to the welding head 1 which is rotated in a horizontal direction, and the portion of the flexible pipe 4 existing outside the pressure pipe b is held by the holding portion 6a of the lift table 6. The holding section 6a is provided with a slide portion 6b provided in parallel with the pipe hole of the pressure pipe b, and the vertical slide 5 is attached to the outside of the pressure pipe b.
Is configured to be held so as to be movable in the axial direction. By finely adjusting the axial movement amount adjuster including the vertical slide 5 and the lifting table 6, the welding torch 2 stored in the welding head 1 needs to be repaired.
Can be properly aligned with the welds of. In addition,
Since the cables for various devices in the welding head 1 and the guide pipe 3 are pulled out to the outside through the flexible pipe 4, the welding work can be easily performed by remote control.

With reference to FIGS. 2 and 3, the welding head 1
Is formed of a cylindrical outer cylinder 10 that can be inserted into a small-diameter pipe hole of the pressure pipe b, and a tip portion 10a that is a warhead shape so as to be easily inserted into the pipe hole. Inside the outer cylinder 10, there are a small welding torch 2, a drive mechanism for driving the welding torch 2, an escape mechanism 20 when the drive mechanism fails, and an arc monitoring mechanism 16 for monitoring the welded portion by the welding torch 2. It is stored. In addition, an opening 10b is provided on one side surface portion of the outer cylinder 10 so that the welding torch 2 can move within the space inside the welded joint that is enlarged like a bag.

Next, a drive mechanism for moving the welding torch 2 in the radial direction with respect to the pipe hole of the pressure pipe b will be described. The welding torch 2 has three long links 7a, 7b and 7c.
It is held at one end side of a parallel link mechanism 9 composed of a short link 8 and one short link 8, and the other end side of the short link 8 is connected to the outer cylinder 10 of the welding head 1, and the long links 7a, 7b and The other end of 7c is connected to the first stage 12 of the linear slide 11. This straight line slide 11
Is attached inside the outer cylinder 10 on the side opposite to the opening 10b of the welding head 1, and the first stage 12 is attached slidably with respect to the linear slide 11. On the other hand, the second stage 12 is also slidably attached to the linear slide 11, but the escape mechanism 2 described later is used.
By holding the rear end portion 1a of the linear slide 11 by 0, the linear slide 11 does not move relative to the linear slide 11.

A motor 14 with an encoder and a feed screw 15 driven by the motor 14 are attached to the second stage 13. One end side of the feed screw 15 is rotatably held by the second stage 13 via a bearing, and the other end side of the feed screw 15 is meshed with a nut that is paired with the feed screw 15 provided on the first stage 12. By the rotation of the screw 15, the first stage 12 moves forward / backward on the linear slide 11 in the pipe axis direction of the pressure pipe b. By moving the first stage 12 in the tube axis direction,
Through the parallel crank mechanism 9, the welding torch 2 moves in the radial direction with respect to the pressure pipe b from the opening 10b of the welding head 1 at the same level.

3 and 4 show an arc monitoring mechanism 16 used for positioning the welding torch 2 and the like. The arc monitoring mechanism 16 is attached to the inside of the welding head 1, and in the present embodiment, a fiber type small CCD camera 17 is used. The CCD camera 17 is the welding head 1
It is preferable that the field of view of the side is provided toward the opening 10b of 1., and the direction of this field of view is preferably at the same level as the level at which the welding torch 2 moves. Further, in front of the field of view of the CCD camera 17, a light-shielding filter 18 that is movable by an air cylinder 19 is provided, and the structure is such that the field of view of the CCD camera 17 is opened and closed vertically. An auxiliary light 30 as shown in FIGS. 2 and 6 is attached to the welding head 1 so as to illuminate the outside of the opening 10b of the outer cylinder 10.

Next, the escape mechanism 20 when the drive mechanism of the welding torch 2 fails will be described with reference to FIGS. 2 and 5. The escape mechanism 20 is provided on the second stage 13 that engages with the linear slide 11, and has two engaging claws 21 a and 21 b that are biased in the direction of being sandwiched by the spring 22.
And a wire rope 23 that opens the two engaging claws 21a and 21b against the spring 22, and the wire rope 23 passes through the guide pipe 3 and the flexible pipe 4 (see FIG. 1) to the outside. Have been led to. Under normal conditions, as shown in FIG. 5 (A), the two engaging claws 2
1a and 21b sandwich the rear end 11a of the linear slide 11. As a result, as described above, the second stage 13 does not move relative to the linear slide 11.

With reference to FIG. 2, a rotary drive mechanism for rotating the welding head 1 in the pressure pipe b will be described. An inner cylinder 24 having an internal gear 24a is connected to the welding head 1 on the guide pipe 3 side, and the welding head 1 and the guide pipe 3 are connected via a bearing housing 25. A motor 26 with an encoder is fixed to the guide pipe 3 so as to engage with the internal gear 24a of the inner cylinder 24. When the motor 26 is driven, the internal gear 24a that engages
The welding head 1 that rotates, that is, is integrated with the inner cylinder 24.
Rotates in the pressure pipe b in the circumferential direction.

Further, a guide ring 27, which is rotatable with respect to the inner wall of the pressure pipe b, is attached to the inner cylinder 24 so as to protrude from the outer cylinder of the bearing housing 25, and when the welding head 1 rotates. The runout of the welding head 1 is prevented. In the present embodiment, the internal gear is provided on the welding head 1 side and the motor is provided on the guide pipe 3 side. However, the internal gear is provided on the guide pipe 3 side and the motor is provided on the welding head 1 side, and the welding head is provided. 1 may be rotated with respect to the guide pipe 3. The guide pipe 3 is provided with guide cylinders 28a and 28b (see FIG. 1) so that the welding head 1 can be easily inserted into the small diameter pipe hole in the pressure pipe b.

Next, the operation of one embodiment of the pipe inner surface welding apparatus according to the present invention will be described. In FIG. 1, first,
Vertical slide 5 having a lifting table 6 at the lower end of the pressure pipe b
After that, the welding head 1 is manually inserted into the small-diameter pipe hole of the pressure pipe b to a bag-shaped space inside the weld joint by a predetermined size. In this case, if the height from the lower end of the pressure pipe b to the floor surface is not less than the rigid body length of the welding head 1 and the guide pipe 3, they can be inserted, and then the flexible pipe 4 is inserted into the guide pipe 3. Can be connected and inserted with a predetermined size. After inserting the predetermined size, the flexible pipe 4 is attached to the holding portion 6a of the lifting table 6.
Then, the arc monitoring mechanism 16 causes the rear surface c of the weld joint to be C
The vertical slide 5 finely adjusts the movement of the flexible pipe 4 in the tube axis direction so that the CD camera 17 comes to the center of the visual field. During the work of confirming the center of the visual field, the light blocking filter 18 shown in FIG.
It is in a position where it does not block the CD camera 17.

After adjusting the position of the welding head 1 in the axial direction of the pipe,
By driving the motor with encoder 14 shown in FIGS. 2 and 6 to rotate the feed screw 15, the first stage 12 starts to move forward along the linear slide 11 in the tube axis direction (see FIG. 6A). ). As the first stage 12 moves forward, as shown in FIG. 6 (B), the parallel link mechanism 9
The welding torch 2 attached to is moved in the radial direction of the pressure pipe b toward the pipe wall within the same level. Here, by numerically controlling the movement amount of the first stage 12 with the encoder of the motor 14, the radial movement distance of the welding torch 2 can be controlled. Together with the arc monitoring mechanism 16, the welding joint back surface c Accurate position setting of the welding start point can be easily performed.

When welding is started, first, the shading filter 18 shown in FIG. 4 is moved to a position where the field of view of the CCD camera 17 is blocked, and the CCD camera 17 is prevented from contamination due to welding.
Is protected and the welding image sent from the CCD camera 17 is made easy to see. Next, welding traveling is performed by rotating the welding head 1 holding the welding torch 2 in the circumferential direction with respect to the pressure pipe b. When the motor 26 with an encoder attached to the guide pipe 3 is driven, the inner cylinder 24 provided with the internal gear 24a meshing with the motor 26 rotates, whereby the welding head 1 coupled with the inner cylinder 24 is pressed against the pressure pipe b. Rotate in the circumferential direction. When rotating, the guide ring 27 guides the core of the welding head 1 to prevent swaying, and stable welding traveling of the welding performed by the welding torch 2 is obtained. The welding range can be easily controlled by the encoder of the motor 26, and continuous welding or spot welding can be performed only at necessary portions.

When the necessary repair welding is completed, the motor 14
In the reverse direction to move the first stage 12 to the second stage 13
The welding torch 2 attached to the parallel link mechanism 9 is housed in the welding head 1 by retreating in the direction approaching. After that, the lifting table 6 outside the pressure pipe b
When the holding portion 6a is removed and the guide pipe 3 and the welding head 1 are pulled out from the pressure pipe b through the flexible pipe 4, the repair welding work of the backside welded portion on the inner surface of the welded joint is completed.

On the other hand, after the completion of the repair welding, the drive mechanism of the welding torch 2 should fail, and for example, the motor 14 or the linear slide 11 may malfunction and the welding torch 2 may be damaged.
When it becomes impossible to store it inside the welding head 1, the escape mechanism 20 shown in FIGS. 2 and 5 is used. As shown in FIG. 5A, in a normal state, the second stage 13 is fixed to the linear slide 11 by sandwiching the rear end portion 11a of the linear slide 11 with the engaging claws 21a and 21b. . However, when the above-mentioned failure occurs, when the wire rope 23 is manually pulled from the outside, the engaging claws 21a and 21b open against the spring 22 and the linear slide is performed, as shown in FIG. The engagement with the rear end portion 11a of 11 is released. Then, due to the weight of the second stage 13 including various parts such as the motor with encoder 14, the second stage 13 slides back along the linear slide 11 and retreats, and is connected via the feed screw 15. The first stage 12, which is present, also retreats. When the first stage 12 retracts, the welding torch 2 is moved to the welding head 1 via the parallel crank mechanism 9.
It is stored inside. As a result, the pressure head 1 can be pulled out from the pressure pipe b.

[0020]

The pipe inner surface welding apparatus according to the present invention comprises a welding torch which is movable in the radial direction with respect to the pipe to be welded, and an arc monitoring device which has a visual field in the moving direction of the welding torch.
A welding head having a drive device for accommodating the arc monitoring device and the welding torch and moving the welding torch in a radial direction, and holding the welding head and surrounding the welding head with respect to the pipe to be welded. A rod member provided with a rotation drive device capable of rotating in a predetermined direction; and an attachment having an adjuster capable of attaching the rod member to the pipe to be welded and adjusting an axial movement amount with respect to the pipe to be welded. Therefore, by inserting the welding head into the pipe hole of the pipe to be welded, the welding torch can be reliably guided to the back side of the welding joint of long pressure pipes, etc., and sound repair welding can be performed. The ease of welding operation leads to stable welding quality and cost reduction.

In the pipe inner surface welding device according to the present invention, the arc monitoring device is a fiber type CCD camera,
Further, since the welding head is provided with a light-shielding filter capable of opening and closing the field of view of the CCD camera, the positioning of the welding torch in the pipe axis direction and the visual confirmation of the welding operation can be easily and surely performed.

[Brief description of drawings]

FIG. 1 is a diagram showing an outline of a pipe inner surface welding apparatus according to an embodiment of the present invention.

FIG. 2 is an enlarged view showing a drive mechanism of a welding head and a welding torch.

3 is a view showing peripheral equipment of a welding torch in a cross section taken along line AA of FIG. 1. FIG.

FIG. 4 is an enlarged view showing an arc monitoring mechanism.

FIG. 5 is an enlarged view showing an escape mechanism of the welding head.

FIG. 6 is a view showing a radial movement of the welding torch.

FIG. 7 is a diagram showing pressure piping attached to an upper lid of a pressure vessel of a nuclear power plant or the like.

[Explanation of symbols]

1 ... Welding head, 2 ... Welding torch, 3 ... Guide pipe,
4 ... Flexible pipe, 5 ... Vertical slide, 6 ... Elevating table, 6a ... Holding part, 6b ... Sliding part, 7a, 7b, 7
c ... long link, 8 ... short link, 9 ... parallel link mechanism, 10 ... outer cylinder, 10a ... tip portion, 10b ... opening,
11 ... Linear slide, 11a ... Rear end part, 12 ... First stage, 13 ... Second stage, 14 ... Encoder motor, 15 ... Feed screw, 16 ... Arc monitoring mechanism, 17 ... C
CD camera, 18 ... Shading filter, 19 ... Air cylinder, 20 ... Escape mechanism, 21a, 21b ... Engaging claw, 22 ...
Spring, 23 ... Wire rope, 24 ... Inner cylinder, 24a ... Internal gear, 25 ... Bearing housing, 26 ... Encoder motor, 27 ... Guide ring, 28a, 28b ... Guide cylinder, 30 ... Auxiliary light, a ... Top lid, b … Pressure piping, c…
The back side of the welded joint.

Front page continuation (72) Inventor Yasuhiro Shoda 1-1-1, Wadasaki-cho, Hyogo-ku, Kobe-shi, Hyogo Mitsubishi Heavy Industries, Ltd. Kobe Shipyard (56) Reference Japanese Patent Laid-Open No. 4-238697 (JP, A) (58) Fields surveyed (Int.Cl. ⁷ , DB name) B23K 9/028 B23K 37/02

Claims (2)

(57) [Claims] 1. A welding torch that is movable in a radial direction with respect to a pipe to be welded, an arc monitoring device that has a field of view in the moving direction of the welding torch, and the arc monitoring device and the welding torch. And a welding head having a driving device for moving the welding torch in the radial direction, and a rotary driving device for holding the welding head and rotating the welding head in the circumferential direction with respect to the pipe to be welded. A pipe inner surface welding apparatus comprising: a rod member; and a fitting having the rod member attached to the pipe to be welded and an adjuster capable of adjusting an axial movement amount with respect to the pipe to be welded. 2. The arc monitoring device is a fiber type CC
The welding head is a D camera, and the welding head is provided with a light blocking filter capable of opening and closing the field of view of the CCD camera.
The pipe inner surface welding apparatus according to 1.